Long Yujia, Leslie William D, Luo Yunhua
Department of Mechanical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
Department of Radiology, Faculty of Medicine, University of Manitoba, Winnipeg, MB R2H 2A6 Canada; Department of Internal Medicine, Faculty of Medicine, University of Manitoba, Winnipeg, MB R2H 2A6 Canada.
Bone Rep. 2015 Apr 8;2:44-51. doi: 10.1016/j.bonr.2015.02.003. eCollection 2015 Jun.
The currently available clinical tools have limited accuracy in predicting hip fracture risk in individuals. We investigated the possibility of using normalized cortical bone thickness (NCBT) estimated from the patient's hip DXA (dual energy X-ray absorptiometry) as an alternative predictor of hip fracture risk. Hip fracture risk index (HFRI) derived from subject-specific DXA-based finite element model was used as a guideline in constructing the mathematical expression of NCBT. We hypothesized that if NCBT has stronger correlations with HFRI than the single risk factors such as areal BMD (aBMD), then NCBT can be a better predictor. The hypothesis was studied using 210 clinical cases, including 60 hip fracture cases, obtained from the Manitoba Bone Mineral Density Database. The results showed that, in general HFRI has much stronger correlations with NCBT than any of the single risk factors; the strongest correlation was observed at the superior side of the narrowest femoral neck with = 0.81 ( < 0.001), which is much higher than the correlation with femoral aBMD, = 0.50 ( < 0.001). The capability of aBMD, NCBT, and HFRI in discriminating the hip fracture cases from the non-fracture ones, expressed as the area under the curve with 95% confidence interval, AUC (95% CI), is respectively 0.627 (0.593-0.657), 0.714 (0.644-0.784) and 0.839 (0.787-0.892). The short-term repeatability of aBMD, NCBT, and HFRI, measured by the coefficient of variation (CV, %), was found to be in the range of (0.64-1.22), (1.93-3.41), (3.10-4.16), respectively. We thus concluded that NCBT is potentially a better predictor of hip fracture risk.
目前可用的临床工具在预测个体髋部骨折风险方面准确性有限。我们研究了使用从患者髋部双能X线吸收法（DXA）估计的归一化皮质骨厚度（NCBT）作为髋部骨折风险替代预测指标的可能性。从基于个体特异性DXA的有限元模型得出的髋部骨折风险指数（HFRI）被用作构建NCBT数学表达式的指导。我们假设，如果NCBT与HFRI的相关性比诸如面积骨密度（aBMD）等单一风险因素更强，那么NCBT可以成为更好的预测指标。使用从曼尼托巴骨密度数据库获得的210例临床病例（包括60例髋部骨折病例）对该假设进行了研究。结果表明，总体而言，HFRI与NCBT的相关性比任何单一风险因素都要强得多；在最窄股骨颈的上侧观察到最强相关性，r = 0.81（P < 0.001），远高于与股骨aBMD的相关性，r = 0.50（P < 0.001）。aBMD、NCBT和HFRI区分髋部骨折病例与非骨折病例的能力，以95%置信区间的曲线下面积AUC（（95% CI）表示，分别为0.627（0.593 - 0.657）、0.714（0.644 - 0.784）和0.839（0.787 - 0.892）。通过变异系数（CV，%）测量的aBMD、NCBT和HFRI的短期重复性分别在（0.64 - 1.22）、（1.93 - 3.41）、（3.10 - 4.16）范围内。因此，我们得出结论，NCBT可能是更好的髋部骨折风险预测指标。
